Will the resulting ABCD matrix from function tf2ss(bf,af), with bf & af defined for a complex filter, work for complex "state"?

A complex filter is whose impulse response is complex valued, and its transfer function in spectral domain could be asymmetric with respect to DC (0 hertz frequency). Let's say bf is the numerator and af is the denominator of this complex filter's transfer function in z-domain already. For example, Hd = (0.007823+6.136e-05i)/(z - (0.9921+0.01558i)),[A,B,C,D] = tf2ss(Hd.Numerator{:},Hd.Denominator{:}) will yield A = 0.9921 + 0.0156i, B = 1, C = 0.0078 + 0.0001i, and D = 0. Can I trust this ABCD matrix will work for the state equations: y(k) = C*x+D*u(k), x=A*x+B*u(k), with x,y and u all being complex valued numbers?

[Star Strider]

The documentation for the Signal Processing Toolbox tf2ss function does not specify that the coefficients must be real.

The Control System Toolbox tf function allows the coefficients to be real or complex.

Create your system, simulate it, and see if it works. The world will not end if it does not.

[Yves]

Thanks

[Star Strider]

My pleasure.